Research on Quantum Field Fluctuations and Gravity

Tufts University, Medford MA

Investigators

Abstract

This project involves theoretical research on several topics related to quantum theory and gravitation. There will be special emphasis on phenomena related to quantum fluctuations. Some of the topics to be investigated include negative energy, fluctuations of the energy density,and the forces on atoms and macroscopic bodies due to the vacuum fluctuations of the electromagnetic field. The work on negative energy seeks to ascertain the limits placed by the aws of physics upon negative energy density, which can be produced by quantum effects.These limits in turn will help to understand better the types of gravitational effects which quantum systems can produce.The study of energy density fluctuations (stress tensor fluctuations) will help to elucidate how quantum fluctuations of matter can give rise to quantum fluctuations of the gravitational field.This may lead to a more precise description of the event horizon of a black hole or the spacetime geometry in the early universe.The work on the forces due to vacuum fluctuations (Casimir forces) will look for systems in which these usually tiny forces can become enhanced. Particular attention will be paid to systems where these enhanced effects might be experimentally observed. This project seeks to integrate studies of the quantum nature of the gravitational field with studies of fluctuating electromagnetic forces. It is hoped that this type of investigation will lead to a deeper understanding of both types of phenomena. This project is expected to have a broader impact through possible benefits to other fields of science, to education, and to technology. The insights and techniques of this work may be useful outside of the specific subfields of physics being investigated. The project will further education through the training of graduate students and by the involvement of faculty at primarily teaching institutions. It should also produce examples which can be used to explain some of the concepts of quantum theory and relativity to students on a variety of educational evels. The work on Casimir forces may eventually be useful in nanotechnology. A better knowledge of Casimir forces is likely to become important for the construction of small scale devices.